Applicant claims priority under 35 U.S.C. xc2xa7119 of German Application No. 202 13 090.8 filed on Aug. 27, 2002.
The invention relates to a device for transplanting trees or shrubs. A device for transplanting trees or shrubs is shown in DE 100 01 078 D1. This device has two spades that can be adjusted and moved between a closed position and an open position by servo-drives. The spades are first driven into an open position, in which they encircle a tree or shrub. By hydraulically adjusting the spades to the closed position, a ball-shaped part of the soil underneath the tree or shrub is cut out. Any roots that may protrude from the ball of soil are cut off. With the spades in the closed position, the ball of soil and the tree can be lifted from the around and transported to a new intended location.
This device has been successfully used in practice and is the starting point of the present innovation. In practical applications, the cutting blades of the spades are subjected to substantial wear, requiring them to be reground from time to time. However, when the grinding treatment of the cutting blades is performed frequently, the spades are shortened, creating a gap between the cutting blades when they are in the closed position. A root protruding into this region can no longer be severed by the spades, and digging the ball from the soil is more difficult if not impossible.
The invention provides a device of the type specified above that has an increased operating time and simple handling.
The device as defined by the invention comprises a carrier preferably structured in the form of a ring. The carrier has two parts that can be separated from each other so that the carrier may be set in a position in which it encircles a tree or bush. Circularly curved slideways are supported on the carrier along with spades, which can be set to either a digging position or a transport position. In the digging position, the spades are retracted to such an extent that the downwardly directed tips are positioned outside of, or aligned below the carrier. These tips encircle the tree or shrub with as much radial spacing as possible. In the transport position, the spades substantially complement each other to form a substantially hemispherical bowl. The a can be removed from the ground. If roots of the tree or shrub protrude from this ball, they are severed as the spades are adjusted and driven from the digging position into the transport position.
It is important that the spades are correctly aligned with each other and form no gaps when in the transport position. To prevent this, the device has guide boxes in which the slideways are accommodated. These slideways are supported on the carrier so that they can be adjusted independently of each other. Thus the individual spades can be precisely adjusted by setting the guide boxes. The cutting blades of the spades are subjected to relatively high wear especially if the device is operated in soil rich in rocks. After the cutting blades of the spades have been reground a number of times, readjusting the guide boxes will compensate for the gap produced between the spades. The device can be operated over a very long time in spite of frequent regrinding of the spades. Only the guide boxes need to be adjusted in this process, which substantially simplifies the operation of the device.
The guide boxes may be support on the carrier in a displaceable manner. However, this would require relatively long adjustment lengths, and thus relatively large-sized adjusting elements. In forming a compact structure of the device, it is more advantageous if the guide boxes are pivotally-mounted on the carrier. Preferably, a bolt supported on the carrier serves as the pivot bearing. Relatively short adjusting means are capable of engaging the upper area of the guide boxes, and the guide bar provides for a sizeable distance of adjustment on the tips of the spades. The clear space within the carrier is not impaired in any way by the adjusting means of the guide boxes. This is important because the tree or shrub has to be accommodated in the clear space when it is dug out.
It is advantageous if the guide boxes are pivotally-mounted on the carrier so that they can be pivoted around a substantially horizontal axis aligned in the peripheral direction. This alignment of the axis of pivot results in an optimal adjustment of the spades. These spades are only driven against each other or away from each other when they are adjusted. The axis of pivot is preferable disposed in the area of the lower end of the carrier.
The guide boxes are preferably fixed on the carrier by least one screw bolt so that there is a safe transmission of forces to the spades. These screw bolts form a safety device for the guide boxes, so that their adjustment is maintained when high forces are acting on the spades in operation. This screw bolt connects the guide box to at least one flange of the carrier for an optimal securing of the guide box on the carrier. The guide box is preferably engaged between two flanges of the carrier. The screw bolt penetrates the guide box and both flanges and clamps these parts against one another. During operation, the screw bolt is exclusively stressed by shearing, so that it is capable or transmitting high forces.
To assure a simple and precise adjustment of the guide boxes, the screw bolt is actively connected to an adjusting mechanism acting substantially radially in relation to the carrier. With the screw bolt released, the adjusting mechanism permits an exact adjustment of the guide boxes. After all the guide boxes have been adjusted, the screw bolts are again screwed to the flanges of the carrier, so that the adjusting mechanism is relieved. Accordingly, the adjusting mechanism has to carry the weight of the guide boxes and spades only during the actual adjusting process.
A simple embodiment of the adjusting mechanism is in the form of a threaded bold that is aligned radially in relation to the carrier. The threaded bolt is supported on the carrier. It is not important for the threaded bolt no engage a threaded bore of a component that is connected in a fixed manner with the guide box or the carrier. By turning the threaded bolt, a relative movement is produced between the carrier and the guide box that can be used for adjusting the guide box. The threaded bolt preferably has at least one surface for engaging a wrench to easily introduce the required torque into the threaded bolt.
Another feature of the adjusting mechanism comprises at least two threaded bolts that are supported one in the other. These threaded bolts have oppositely directed threads. The inner threaded bolt engages a female thread of the outer threaded bolt, wherein a setting movement of the outer threaded bolt leads to an adjustment of the inner threaded bolt over twice the distance. This provides for relatively long adjustment movements, whereas the size of the overall structure of the adjusting mechanism remains small. The space available above and below the carrier can be optimally utilized without impairing the clear space formed by the carrier.
Another feature of the adjusting device, comprises a first receptacle that is engaged by the screw bolts for fixing the guide boxes. This receptacle is transversely penetrated by a threaded bore that receives the threaded bolt of the adjusting mechanism. Thus there is formed a particularly compact structure of the adjusting mechanism. The threaded bore of the receptacle preferably receives the outer threaded bolt of the adjusting mechanism.
Finally, it is favorable if a second receptacle is supported on the threaded bolt, preferably on the inner threaded bolt. This second receptacle is preferably formed by a piece of tubing that is connected with the threaded bolt and extends transversely in relation to the latter. This tubing is penetrated by a bearing pin. This bearing pin is preferably formed by the pivot hook fixing the guide box. This pivot hook is supported on the carrier, specifically on the flanges of the carrier, or on the guide box, forming a simple and effective abutment for the adjusting device.